As a kid, the UFC heavyweight champion was kind of a crybaby, if you want to know the truth.

Overly sensitive, eager to avoid confrontation and terrible at sports, especially soccer, which is still nearer to a religion than a sport in his home country of Brazil, Junior Dos Santos never expected to grow up to be an athlete, much less the baddest man on the planet.

He never even expected to be the baddest man in his tiny hometown of Cacador, where he sold ice cream on the street as a child to augment his family’s meager income.

Now look. The sensitive kid has become a 6-4, 240-pound knockout artist who rules one of the most dangerous divisions in sports. He’s not certain how it happened, but he’s pretty sure he was born with this inside him. It just took a long time to come out, he told MMAjunkie.com (www.mmajunkie.com).

“I never expected this,” said Dos Santos, 28, who became the UFC heavyweight champ with a firstround knockout of Cain Velasquez in November 2011 in what is still the UFC’s most watched fight on the Fox network.

“As a kid, I was never really good at any sports. … When I found fighting, I feel like I found myself. I found where I belong and what I’m supposed to be doing.”

It helps that Dos Santos is pretty good at it. In roughly five years, he went from novice to UFC champion while handing out vicious beatdowns to some accomplished big men in the world’s foremost mixed martial arts organization.

But even though Dos Santos is acknowledged as the world’s top heavyweight, anyone who has seen him outside the cage might have a hard time thinking of him in the same terms as the other tough-guy fighters who have held that distinction.

In the days of Mike Tyson and Sonny Liston, the boxing heavyweight champ was commonly thought of as the “baddest man on the planet.” Even in MMA, when glowering tough guys such as Brock Lesnar held the UFC strap, there was little doubt the heavyweight champ would be the first pick when sides were chosen for a rumble.

But Dos Santos? The man can barely stop smiling long enough to look mean. When UFC cameras followed him around his hometown for a promotional piece before his first fight with Velasquez, the most threatening thing he said was when he asked star-struck children, over and over, “Where’s my hug?”

It’s hard not to look at him and wonder, how can this be the baddest man alive?

“It’s funny, I was thinking about that recently,” Dos Santos said. “My goal was to be the baddest man on the planet. I wanted to be the champ, and the champ of the top category — the heavyweights. But now, if I’ve actually got to be bad to be the baddest man on the planet, then I don’t want it. I’m a nice guy.”

He made it about one minute into their title fight before being planted face-first on the canvas by Dos Santos’ right hand. That’s the thing about the heavyweights, the thing that makes them so exciting to watch and yet so unpredictable.

As Dos Santos put it, “In the arena, watching us live, you can hear when a heavyweight punch connects. It doesn’t matter where in the arena you are. People like to see that power. Heavyweights finish fights.”

That unpredictability also is what has made the UFC heavyweight title a lot easier to win than to defend. Dos Santos is the fifth man in four years to call himself UFC heavyweight champ and the first since Lesnar to have successfully defended it at least once.

His rematch with Velasquez should go a long way toward determining whether he’s the man to bring stability and consistency to the heavyweight throne or whether the belt will continue to be passed around like an unwanted object.

Now that Dos Santos is the champ, he has an idea of what it must have meant for Velasquez to lose in their first meeting.

“I saw his interviews after our last fight, and I’ve seen his interviews recently,” Dos Santos said. “I saw how upset he was to lose the title, and I know how badly he wants to get it back. You can see that very clearly in him.”

But while Velasquez is likely depending on using his wrestling skills to dethrone the champion, Dos Santos is depending on something a little more in keeping with the heavyweight tradition of big men doing bad things.

“Cain Velasquez might be able to take me down,” he said. “He might be able to take me down 10 times. But for each of those times he takes me down, I’m going to stand back up.

“If I land 10 punches on Cain Velasquez, he’s not going to stand back up.”

As the UFC 189 tour made its last stop in Dublin, featherweight champ Jose Aldo was met with a torrent of abuse from the Irish fans. It might have been unpleasant, but it might also have been just what he needed.